Overnight pH drop? 7.1 to 6.0

[JamesHitt74]

I am a little baffled here. I keep a 10g in the house as well as a 120 long. I checked the pH before I went to bed at 10pm, was at 7.1 (tripple checked). At 6 this morning, it was 6.0 (tripple checked). hob aqua-tech #2 10-20gal. Fish are 1 pictus cat, 1 Ch. algae eater, 1 Dwarf Gourami, 1 Bristle nose plec, 1 Electric Yellow Af. Cichlid. Have had tank set up for 8 months. I do 1/4 water changes weekly. Did my KH drop out or what? I have done a 1/2 water change and adjusted to 7.2 using baking soda and treated water solution. Fish seem fine. No ammonia, and no nitrites. What took place here? Any advice is welcome.

 

[JamesHitt74]

This was posted in the wrong area. My appologies to all. How do I fix this?

 

[ccCapt]

I moved your post to the freshwater section.

 

[Convict2161]

Just curious do you have driftwood or plants? Also pH can "swing" get a bucket and fill it. Test it and leave it over night then test again and see if it's stable. That's a good way to determine if it's a tank issue or a tap. I'm gonna guess and say it's the tap water. Maybe get a KH/GH test kit? Test alkalinity?

I'm still learning but this is something I had to do and found out my tap water was dropping overnight if left in a 5 gallon bucket. I use Malawi Buffer and crushed coral in a bio bag and have been stable since.

Someone with more knowledge will chime in I'm sure. Sorry I couldn't be more help.